"I emphasize personal liberties. I don't like a managed economy, whether it's through central economic planning or monetary policy or even Congress doing it. It's a completely different philosophy that markets are supposed to work, you know, in a natural way," the Texas congressman said.

Krugman, meanwhile, described Paul as "living in the world that was 150 years ago."

“History tells us that in fact a completely unmanaged economy is subject to extreme volatility, subject to extreme downturns. I know this legend that some people like that the Great Depression was somehow caused by the government or the Federal Reserve, but that's not true. The reality is it was a market economy run amok, which happens repeatedly," the Nobel Prize-winning economist said.

That prompted Paul to one-up Krugman, saying the columnist "wants to go back 1,000 years or 2,000 years just as the Romans and the Greeks and all other countries debased their currency."

"What did the Romans do to their currency? The Byzantine Empire had a gold standard for a thousand years and they did quite well and they didn't fight wars. But the Roman empire eventually destroyed their currency. They put in wage and price controls before they diluted the metals. They inflated. They thought wealth could come by fooling the people," Paul said.